Radio Frequency Magnetron Co-sputtering Method Research Articles

Growth of High-Quality Perovskite KTa1-xNbxO3 Thin Films by RF Magnetron Co-Sputtering

In this study, we demonstrate the growth of high-quality KTa1-xNbxO3 (KTN) thin films by using multi-target radio frequency (RF) magnetron co-sputtering with KTaO3, KNbO3, and K2CO3 targets. KTaO3 and KNbO3 targets were used to control the Ta/Nb ratio while the K2CO3 target was used to supply excess potassium (K) to compensate for the K deficiency. Through careful control of the RF powers applied to each target, high-quality perovskite KTN (x = 0.53) thin films were grown on various single crystal substrates. Variable temperature Raman spectroscopy revealed that the KTN thin films exhibit a ferroelectric phase at room temperature with a Curie temperature of ~403 K. The optical constants n and k of the KTN thin film were also similar to those reported for single KTN crystals. These results present a simple route toward fabricating high-quality perovskite KTN thin films with desired structural and optical properties for various device applications utilizing the RF magnetron co-sputtering method.

Trace amount of niobium doped [formula omitted]-Ga[formula omitted]O[formula omitted] deep ultraviolet photodetector with enhanced photo-response

The growth of trace amount of niobium (Nb) doped β-Ga2O3 thin films have been demonstrated on (0001) sapphire substrates by radio frequency magnetron co-sputtering method. The crystallization, morphology and optical properties of Nb doped β-Ga2O3 films have been investigated. The deep ultraviolet (DUV) photodetector with a metal–semiconductor–metal structure based on trace amount of Nb doped β-Ga2O3 thin film was fabricated. The DUV photodetector exhibits high photo-to-dark-current ratio and fast photo-response speed, suggesting the performance of β-Ga2O3 photodetector can be improved by doping trace amount of Nb in β-Ga2O3 thin film.

Threshold resistance switching in silicon-rich SiOx thin films**Project supported by the Open Project Program of Surface Physics Laboratory (National Key Laboratory) of Fudan University, China (Grant No. KF2015_02), the Open Project Program of National Laboratory for Infrared Physics, Chinese Academy of Sciences (Grant No. M201503), Zhejiang Provincial Science and Technology Key Innovation Team, China (Grant No. 2011R50012), and Zhejiang Provincial

Si-rich SiOx and amorphous Si clusters embedded in SiOx films were prepared by the radio-frequency magnetron cosputtering method and high-temperature annealing treatment. The threshold resistance switching behavior was achieved from the memory mode by continuous bias sweeping in all films, which was caused by the formation of clusters due to the local overheating under a large electric field. Besides, the I–V characteristics of the threshold switching showed a dependence on the annealing temperature and the SiOx thickness. In particular, formation and rupture of conduction paths is considered to be the switching mechanism for the 39 nm-SiOx film, while for the 78 nm-SiOx film, adjusting of the Schottky barrier height between insulator and semiconductor is more reasonable. This study demonstrates the importance of investigation of both switching modes in resistance random access memory.

Post-annealing effect on the a-SiCx passivation layer synthesized with the radio frequency magnetron co-sputtering method

The amorphous silicon carbide (a-SiC) film has been considered a good candidate for the rear passivation layer of the high-efficiency silicon solar cell. We describe the results of the post-annealing of an amorphous silicon carbide (a-SiC) film deposited using the radio frequency magnetron sputtering method. The post-annealing was performed with rapid thermal annealing process in three different chamber environments: nitrogen (N2), oxygen (O2), and hydrogen (H2). After the annealing process, the characteristic properties of the films were investigated in several categories. The transmittance of the film was measured with Scinco s-3100 at the 400–800nm wavelength. The average transmittance increased after the annealing treatment, and the highest transmittance was achieved with the H2 ambient. Using a silicon wafer lifetime tester, we measured the carrier lifetime of the films. We found that the carrier lifetime was highest in the N2 ambient annealing process. Also, the refractive index was determined using an ellipsometer. The measurement indicated that the refractive index of the film decreased in the annealing process, unlike that of the as-deposited film.

Preparation and characterization of self-assembled percolative BaTiO3–CoFe2O4 nanocomposites via magnetron co-sputtering

BaTiO3–CoFe2O4 composite films were prepared on (100) SrTiO3 substrates by using a radio-frequency magnetron co-sputtering method at 750 °C. These films contained highly (001)-oriented crystalline phases of perovskite BaTiO3 and spinel CoFe2O4, which can form a self-assembled nanostructure with BaTiO3 well-dispersed into CoFe2O4 under optimized sputtering conditions. A prominent dielectric percolation behavior was observed in the self-assembled nanocomposite. Compared with pure BaTiO3 films sputtered under similar conditions, the nanocomposite film showed higher dielectric constants and lower dielectric losses together with a dramatically suppressed frequency dispersion. This dielectric percolation phenomenon can be explained by the ‘micro-capacitor’ model, which was supported by measurement results of the electric polarization and leakage current.

Tribological properties of a-C:W film deposited by radio frequency magnetron Co-sputtering method

We deposited the tungsten doped amorphous carbon (a-C :W) film on silicon (Si) substrate by radio frequency (RF) magnetron co-sputtering method. Tungsten (W) was used as the doping metal of a-C film. Carbon and metal components were deposited simultaneously on the Si substrate by co-sputtering method, and the applied RF power on the graphite (C) was 150W and it on tungsten (W) metal target was from 20W to 50W, respectively. In this work, the influence of RF power in W target on the structural, physical, and tribologcal properties of the a-C:W films was experimentally investigated. The hardness increased with increasing RF power in W target and exhibited the maximum hardness value about 18.5GPa at the condition of RF power in W target, and the adhesion and surface roughness properties improved with increasing RF power in W target. However the friction property is declined with increasing RF power. Consequently, the improvement of physical properties in a-C:W films is associated with the enhancement of energetic ions bombardment and the increase of W contents in amorphous matrix by increasing RF power in W target.

Characterisation of 12CaO.7Al2O3 insulator and electride doped indium tin oxide thin films for OLED applications

In this study, 12CaO.7Al2O3 (C12A7) insulator and electride doped indium tin oxide (ITO) (ITO:C12A7 insulator and electride) films were deposited on glass substrates by an radio frequency magnetron co-sputtering method with increasing number of C12A7 insulator and electride chips. The carrier concentration of both films was slightly decreased with increasing number of C12A7 insulator and electride chips to a minimum value of 7·8×1019 cm−3. On the other hand, the resistivity of the films increased gradually with increasing number of C12A7 insulator and electride chips to maximum value of 8·1×10−3 Ω cm for seven chips in the films. The decrease in carrier concentration and increase in resistivity can be related with the crystallinity of the films. The structural property and surface roughness of the films were examined and the change of grain size was strongly dependent on the decrease in crystallinity and surface roughness.

O K-energy loss near-edge structure change induced by tantalum impurity in monoclinic hafnium oxide

The present paper reports the energy loss near-edge structure (ELNES) study of monoclinic HfO2 (m-HfO2) and tantalum doped m-HfO2 (Ta0.1Hf0.9O2) thin films prepared by radio frequency magnetron co-sputtering method. A change in the O K-ELNES spectra was observed as the amount of dopant increases. In order to precise the common features and the differences as a function of Ta defect nature (substitutional or interstitial) in HfO2, the O K-ELNES were commented with respect to density functional theory calculations implemented in Vienna ab initio simulation package code. The calculated Ta doped HfO2 band structure showed that substitutional tantalum is the dominant defect and the spectral differences between doped and non-doped HfO2 are mainly originated from the change in the local cation distribution around the oxygen atoms.

Effects of Al content on the properties of ZnO:Al films prepared by Al2O3 and ZnO co-sputtering

Aluminum doped zinc oxide (AZO) films were deposited on quartz substrates by radio-frequency magnetron co-sputtering method with ZnO and Al2O3 ceramic targets. The structural, optical and electrical properties of these films as a function of the Al content were investigated. XRD results reveal that the AZO films are wurtzite structure with (002) preferred orientation. The average transmittance of all the films is higher than 80% in a wide wavelength range from 400 to 1,500 nm. The band gap energy, calculated from their optical absorption spectra, is in the range of 3.50–3.66 eV depending on the Al content. Doping of Al3+ in the ZnO makes the film surface roughness decrease. The dopant Al3+ acts as electron donor by which the electrical conductivity and carrier concentration of the films are obviously increased until the Al3+ reaches its saturation content of about 4.50 at.%.

Fine structure of the plasmon resonance absorption peak of Ag nanoparticles embedded in partially oxidized Si matrix

Ag/Si nanocomposite films were prepared by the radio-frequency magnetron cosputtering method. The fine structure of the plasmon resonance absorption peak was found in film samples. X-ray photoelectron spectroscopy analysis indicated that the samples were composed of a two-layer structure, which accounted for the structure of the optical absorption spectra. The peak located near 445 nm is the plasmon resonance absorption peak of Ag nanoparticles embedded in a partially oxidized Si matrix. Its intensity decreases with decreasing film thickness and disappears in a very thin sample. The peak located near 380 nm originates from the plasmon resonance absorption of the thoroughly oxidized surface layer of the sample. Its intensity does not change with increasing thickness, but it cannot be observed in the very thick sample.